1) if you cant pull up the window switches, check if it is screwed on the door trim. There is a screw hole some cm lower than the switches, usually the screw is missing but perhaps your car is fully equiped
2) i m not sure about the exact offset, depends on the speaker, but you should have the minimum spacer dimensions as long as the window can work up and down without touching the speakers magnet.
3) BE CAREFUL. My speakers (Utopia) were touching the door trim and i almost damage the speaker's rubber. Make your spacers as short as possible like i said above. The Polyglass dont have that big magnet
but its not small than Banlfu's (
) either so better safe than sorry.
4) The magnet's field is not variable so it doesnt induct any currents on the crossover, but there is mechanical interference due to the bass virbations to the crossover's coils. Thats why all the elements
on the crossover are glued and tighted on the pcb ( the second reason for this are the Laplace forces at the coils' rounds.)
Don't fit the crossovers on the woofers, but dont put the crossovers kilometers away either. Under the arm rest will be just fine.
5) Set the tweeter's level at the lowest possible from the crossover. The tweeters are too close to the ears in the 147. Avoid using the
equalizer unless its necessary, because it solves magnitude problems but it creates phase ones at the frequency response. If you find the
tweeter still strong after the lowest crossover setting, we ll make an Lpad for the specific dB you wish to lower them more.
PS: Your crossover must have a switch for the midrange level too, try playing with it also to see which setting gives the more balanced sound in your car. Try different cd's with different kind of music before ending up to a final setting.